Golly is an open source, cross-platform Game of Life simulator currently under development by Andrew Trevorrow and Tomas Rokicki. Our goal is to write a world-class Life simulator, solicit ideas and help from the planet's best Life hackers, and share some of our excitement.
Golly's key features:
• Unbounded universe (limited only by memory).
• Fast, memory-efficient conventional algorithm.
• Super fast hashing algorithm for highly regular patterns.
• Responsive even while generating or garbage collecting.
• Reads RLE, Life 1.05/1.06, and macrocell formats.
• Can paste in patterns from the clipboard.
• Auto fit option keeps patterns sized to the window.
• Full screen option (no menu/status/tool/scroll bars).
• Built-in HTML help system (thanks to wxWidgets).

Version 2.4:

* Fixed bug that prevented 64-bit Windows app using more than 4GB of hash memory.
* Fixed bug that caused corrupted macrocell files if saved with timeline data.
* Fixed bug in Langtons-Ant.tree that had ants colliding incorrectly.
* Fixed Mac app crashing if user's language setting is non-English.
* Clipboard data on the Mac now uses LF as the end-of-line character rather than CR.
* A pending paste is aborted if the main window becomes inactive.
* Error messages from each algorithm are shown if a pattern file can't be loaded.